It took hours for the Internet to strike back. Yesterday, the Anonymous hacker-activist collective accepted credit for taking down the websites of several government agencies, music trade groups and major record labels. By the end of Thursday, the online hubs of the Department of Justice, the FBI, the Copyrights Office, the MPAA, the RIAA, BMI, Universal Music and Warner Music were all taken offline.

Anonymous spokesperson Barrett Brown confirmed that yesterday's coordinated attacks were in retaliation to the Megaupload shutdown by the federal government and intended to "damage campaign raising abilities of remaining Democrats who support SOPA."

The pressure imposed by the MPAA to wipe out digital piracy has been at an all-time high recently with SOPA and PIPA circulating in Congress. Silicon Valley's protest against the legislations culminated this Wednesday with Wikipedia's 24-hour blackout. That day, Google, Tumblr and Reddit also encouraged users to sign petitions opposing the two bills.

"Let's just say, for #SOPA supporters their #SOPAblackout is today," the official Anonymous Twitter account boasted in reference to the website take-downs and alluding to the Wikipedia blackout that occurred the day before.

Thursday's strike on government and entertainment sites was the largest Anonymous operation to date, with 5,635 computers running distributed attack software. Similarly, in 2010, Anonymous shut down the PayPal, Visa and MasterCard websites after they decided to freeze all donation transactions to Wikileaks.